1. Field of the Invention
The present invention relates to a battery pack, and more particularly, to a battery pack that can secure the mounting space of a circuit device in a circuit module, can simplify the assembling process of a bare cell and a circuit module, and can miniaturize the battery by lowering the height between the bare cell and the circuit module.
2. Description of the Related Art
In general, as portable wireless devices such as video cameras, mobile phones, and portable computers become lighter and highly-functionalized, studies on secondary batteries used as drive sources of portable wireless devices are being widely carried out. Secondary batteries include nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium secondary batteries. Of the secondary batteries, since lithium secondary batteries can be rechargeable and miniaturized and can have a high capacity, they are being generally used in high-tech electronic device fields due to their high operation voltages and energy densities per weight.
A lithium secondary battery has the form of a battery pack. The battery pack includes bare cell having an electrode assembly with a positive electrode plate, a negative electrode plate and a separator. The pack further includes a can accommodating the electrode assembly and a cap assembly sealing the top opening of the can. The pack further includes a circuit module having a circuit device, such as a charge/discharge device and a protection circuit device, which is coupled to the bare cell The pack also often includes and an outer cover covering the circuit module.
Typically, the bare cell and the circuit module are electrically connected to each other by a first lead plate and a second lead plate. However, since the first lead plate and the second lead plate are generally mounted to a surface of the circuit module, large spaces for mounting the first lead plate and the second lead plate are necessary. Accordingly, this limits the mounting of a plurality of circuit devices in or on the circuit module. Moreover, since the first lead plate and the second lead plate are mounted to a surface of the circuit module, the total length of the battery pack becomes longer, making it more difficult to miniaturize the battery pack.
In addition, since the first lead plate is generally located at a central portion of the top of the bare cell and the second lead plate is generally located on one side thereof, the circuit module disposed on the bare cell often cannot be horizontal. Accordingly, the circuit module is often deflected to one side of the battery pack and this makes the quality of the battery lowered.